CVE catalog

CVE-2026-55962

Severity: Medium · CVSS 6
Published: Jun 25, 2026, 10:17:02 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.24% · Oct 25, 2026

TLS 1.3 post-handshake authentication (PHA) issue where a server could accept a client's Finished message without the client having sent a Certificate and CertificateVerify. The post-handshake-auth exemption that allows an empty/absent peer certificate was only intended for the initial handshake, but it was also being applied while a post-handshake CertificateRequest was still outstanding. The check is now scoped to the initial handshake only: on the server, once a post-handshake CertificateRequest has been sent (certReqCtx is set), a peer certificate and a valid CertificateVerify are required again before the Finished is accepted, with empty-certificate handling following the configured verify mode (FAIL_IF_NO_PEER_CERT) just as during first-handshake client authentication. Only affects TLS 1.3 servers built with post-handshake authentication support (WOLFSSL_POST_HANDSHAKE_AUTH / --enable-postauth, included in --enable-all) that enable WOLFSSL_VERIFY_POST_HANDSHAKE and request a client certificate after the handshake via wolfSSL_request_certificate(). Clients, and servers that do not use post-handshake authentication, are unaffected.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	wolfssl	sid	`5.9.2-1.2`	fixed
Debian	wolfssl	trixie	`5.7.2-0.1+deb13u2`	fixed
Debian	wolfssl	bookworm	`5.5.4-2+deb12u2`	vulnerable
Debian	wolfssl	bookworm-security	`5.5.4-2+deb12u3`	fixed
Cpe	wolfssl	Not reported	Not reported	vulnerable
Cpe	wolfssl	Not reported	`5.9.2`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	wolfssl	source	sid	`5.9.2-1`	not yet assigned	Not reported	[1140815]
Debian	wolfssl	source	trixie	`5.7.2-0.1+deb13u2`	not yet assigned	Not reported	[1140815]
Debian	wolfssl	source	bookworm	`5.5.4-2+deb12u3`	not yet assigned	Not reported	[1140815]
Cpe	wolfssl	cpe	Not reported	`5.9.2`	Not reported	Not reported	Not reported

[Debian bug #1140815]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libwolfssl35]Affected
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Affected · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Affected · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Fixed · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Fixed · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
[libwolfssl-dev]Affected
Source package: [wolfssl]
Details (4)
- 5.5.4-2+deb12u2 · amd64 · bookworm
  Affected · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u2 · arm64 · bookworm
  Affected · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · amd64 · bookworm-security
  Fixed · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- 5.5.4-2+deb12u3 · arm64 · bookworm-security
  Fixed · Fixed: 5.5.4-2+deb12u3
  nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12

[Debian 13 (Trixie)]

[libwolfssl42t64]Affected
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Affected · Fixed: 5.7.2-0.1+deb13u2
  nvd · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Affected · Fixed: 5.7.2-0.1+deb13u2
  nvd · wolfssl · debian · 13
[libwolfssl-dev]Affected
Source package: [wolfssl]
Details (2)
- 5.7.2-0.1+deb13u1 · amd64 · trixie
  Affected · Fixed: 5.7.2-0.1+deb13u2
  nvd · wolfssl · debian · 13
- 5.7.2-0.1+deb13u1 · arm64 · trixie
  Affected · Fixed: 5.7.2-0.1+deb13u2
  nvd · wolfssl · debian · 13

Observed: Oct 23, 2026, 9:45:23 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]